Method and apparatus for fiberizing molten material



METHOD AND APPARATUS FOR FIBERIZING MOLTEN MATERIAL Filed Sept. 29, 1948E. R. POWELL Aug. 29, 1950 2 Sheets-Sheet l l7 INVENTOR.

{OW/4P0 x? Pay 44,. 121 4/ fi Armlemsy Aug. 29, 1950 E. R POWELL METHODAND APRARATUS FOR FIBERIZING MOLTEN MATERIAL Filed Sept. 29, 1948 2Sheets-Sheet 2 INVENTOR. fa /4P0" A. flan/ELL.

ATTORNEY.

Patented Aug. 29, 1950 METHOD. AND APPARATUS, FOR FIBERIZING BIOLTEN.MATERIAL Edward-R. Powell; North Plainfield, N. J assignor to Johns-Manville Corporation, New: York, N. Y.,, a corporation of New YorkApplication September 29, 1948; Serial No. 51,750

1 12 Claims: The present invention relates tothe manufacture of mineralwool and, more particularly, to an improved apparatus and method forconverting a molten mineral material into fibers. iheapplication is acontinuation in part as to all common subject matter with my copendingapplication, S. N. 742,054, filed April 17, 1947" now abandoned which,in turn, was a continuation in part of copending application's, S. N.485',009,filed April29, 1943, now Patent No. 2,428,810 and-S. N.555,359, filed September22, 1'9el4.v The term mineral wool is employedin the instant application as in my said priorapplications, in a genericsense to include wool or fibers formed from'rock, slag, glass, mixturesthereof and like raw materials.

Heretofore molten raw-materials of the type referred to above havebeenconverted into fibers-in. a number of ways, including the commonlyused method of disintegrating-a stream of the molten material by theaction of: ahigh pressure steam jet. More recently, it has beenproposed; to fiberize the material by a spinning process in which thestream is discharged onto spinners or rotors rotated at high speed, thecentrifugal forces set up causing portions; of the material to leave therotors and to be drawn into fillers. "The instant invention has,forit'sjprincipal object the provision.

of'an' improvedapparatus and method of the lat.- ter type which will.handle larger quantities of the molten material, provide a greater fiberyield, andproduce finer and more uniform fibers.

One of the major difficu'lties, of" adapting the spinning method tooperations on a commercialscale has been the inability of the equipment;to efiectively handle the outputof' the modern cupola conventionallyused in mineral wool operations. An object ofthe instant inventionis'th'e provision of an improved apparatus and-method employing aplurality of rotors or-spinners which secure a wider distribution orspreading ofthe' molten material to substantially increase thefiberization area and, hence, the capacity and efficiency of theoperation.

Another objectof'the invention is the provisionofi a1 method andapparatus in which the movement of the molten material is graduallyaccelerated. as its passes through the equipment and, at thev same time,the stream is gradually: divided or spread, whereby conversion of thegreater portion of the; stream into fibers, with only a.

minimmn'. of unfiberized particles or shot" is. achieved;

It has been found that. by the present method. a fiber yield as highas.45 can be obtained on a commercial scale in. contrast to. the conven.tional blowing operations where it has beenv unusual to. obtain yieldsgreater than, say, 27% 01" the molten slaga Furthermore, the fibers:pro:- duced arelonger and liner than those obtained by: the.priorprocesses and a cleaner, more shot! free product isv achieved.

My'invention willibe more fully understood: and. further objects. andadvantages thereof will be-- come apparent when reference is made. tothe; more detailed description which is to follow and; to-theaccompanying drawings in which:

Fig. 1 is a diagrammatic, front elevationalview: of apparatus embodyingthe invention;

Fig. 2 is-v a top. plan View of the fiberizing apparatus of Fig. 1;

Fig. 3 1s a side elevational view of the fiberizing" apparatus of Fig.'1.

Fig. 4' is a viewsimilar to Fig. 3-but with parts broken away,illustrating a minor modification of" the invention; and

Fig. 5 is a view similar to Fig. 1 but illustrating the modificationofFi'g. 4".

Referring now to the daw-ings, there is shown an apparatuscomprising amelting furnace m:

which may be ofany suitable type, such as: a

cupola, tank furnace, or the like. The furnace includes a discharge;trough [2 from which a stream of-molten material is drawn from thefurnace and discharged in position for fiberization.

: Thai-awmaterialmelted in the furnace and converted into the moltenstream may be rock, slag, glass, mixtures thereof, or other liquefiablematerials, suitable for conversion into fibrous wooli by the methodhereinafter described, allsuchman-- terials: being herein referred to asmineral materials.

The major fiberizin operation isperformed by a pair of rotors i6 and 18?having relatively wide,

peripheral surfaces I? and it, respectively. The rotors are mounted forrotation on shafts 2115 and 22, respectively, the shafts. as bestillustrated in Fig. 2, preferably extending at. a. slight angle; say,anangleof 9to each other.

Rotors 8:6 andv 5.8. are. driven in opposite directions; as. indicated;the arrows, and at. rela tively high speeds. The rotors are ofheat-resistant steel or other alloy of a character to resist the hightemperature of the material, which may run as high as 2900 F., withoutexcessive erosion or wear. The surfaces of the rotors are alsopreferably provided with a series of grooves 24, suitably of U-shape, toinsure the bonding of a ring or rings of the molten material thereto,although bonding of the rings is not necessarily dependent on suchgrooves. It has been found that, even if plane surfaced rotors are used,after the rotors are subjected for a period of time to the action of themolten material, the latter will tend to bond to the surfaces. However,the use of more positive means for this purpose, such as the grooves 23,15 preferred.

Supported above the main fiberizing rotors l6 and I8 are a pair ofrotors 26 and 28. Rotors 2B and 28 are supported on shafts 30 and 32,respectively. Shaft 32 lies in an approximately horizontal planesubstantially parallel to the planes of shafts 2i) and 22, but shaft 35preferably extends upwardly at a small angle to define an acute angle,say, an angle of about 6 between the planes of the shafts, asillustrated. Rotors 26 and 28, similarly to the other rotors, havesurfaces of steel or other heat-resistant metal, capable of resistingthe temperatures of the molten material without excessive erosion.Rotors 26 and 28 constitute what is, in effect, a stream spreading ordistributing device, although, particularly rotor 28, also performs afiberizing funct on as will be later pointed out.

In the form of the invention illustrated in Figs. 1, 2 and 3, the rotors26 and 28 are of frustoconical form with the coned surfaces preferablyin reversed relationship. Rotor 25 may be smooth surfaced, asillustrated, while rotor 28 may be provided with one or more grooves 34of relatively large cross-section. It will be appreciated that thesegrooves, as well as the grooves in the main fiberizing rotors, are shownof somewhat exaggerated size. In the embodiment illustrated in Figs. 4and the upper rotors, indicated in these figures by the referencecharacters 33 and 38, are of cylindrical, rather than conical form.Rotor 36 preferably has a deep groove All, while the surface of rotor 38is preferably smooth. This embodiment of the invention is otherwisesimilar to the previous embodiment.

The several shafts are supported from a suitable framework 42 onbearings M. At least the front bearings are carried by yieldablemountings of any suitable or conventional type which will permit therotors to move apart in the event a solid chunk of slag or fuel shouldfall between them. The rotors may be driven by individual motors or by asuitable drive, illustrated only diagrammatically, and mounted in anydesired location on the frame structure 42. The drive is arranged sothat the rotors 2i; and 28 or 36 and 38, as the case may be, rotate inopposite directions, as indicated by the arrows in Figs. 1 and 5, withtheir upper surfaces approaching, and rotors l5 and IB also rotate inopposite di-- rections with their upper surfaces approaching, aspreviously mentioned.

In the operation of the apparatus described above, and in carrying outthe method of the instant invention, the fiberizing device is positionedto have the molten material stream issuing from the cupola impingeagainst rotor 26 or 36, depending upon the embodiment of the inventionemployed, at a point to the right 0f.a

vertical line through the axis of the rotor, as viewed in Figs. 1 and 5;that is, on a downturning segment of the rotor. This is diagrammaticallyillustrated in Figs. 1 and 5 where the course of the main bod of thestream to the initial rotor and from there through the equipment isindicated by broken lines. The rotors are tilted to have the shaftsslant downwardly, shafts 20, 22 and 32 extending at an angle of about 12to the horizontal, as indicated in Fig. 4 but retaining What is hereintermed an approximately horizontal position. The main purpose of thetilting of the shafts is to avoid interference between the fibers beingformed and the molten stream. Inasmuch as the fibers are drawn out inplanes approximately at right angles to the shafts of the rotors bywhich they are formed, if the shafts are horizontal, at least part ofthe fibers are projected directly into the path of the stream. It willbe appreciated that, as indicated in Fig. l, the rotors are forwardly ofthe melting furnace I0.

Molten material issuing from the cupola and forming a molten stream isin a highly fluid, incandescent condition and, for economy, the streamis of considerable size of, say, diameter. The condition of fluidityemployed for the molten material in mineral wool fiberization by theconventional steam jet process is an example,

although somewhat more fluid streams may be used if desired. The rotorsare driven at successively higher speeds to constantly accelerate themovement of the molten material on its way to fiberization. Also, thecontact with the first 4 .rotor is at only a slight angle to avoidspattering this very large and flu'd stream. As the stream is graduallydispersed, it is possible to direct it more directly against thesurfaces for better bonding. Thus, the impact on the first rotor surfaceis nearly tangent to it while the impact on the surface of rotor 16 maybe substant'ally perpendicular. The molten material impinging upon rotor26 or 36 is only lightly bonded, if bonded at all, and is discharged ata greatly accelerated speed and in a spread, distributed. or partiallydisintegrated condition onto the peripheral surface of rotor 23 or 38,as the case may be. The spread'ng of the material apparently is causedin most part by the separation of the stream into a plurality ofcomponents as it leaves the initial rotor. In the embodiment of Figs.1-3, spreading is further encouraged by the fact that some of thematerial is discharged at approximately right angles to the rotor axis,and other of the material is discharged approximately normal to theconical surface. However, it has been found that the rotors of the formshown in Figs. 4 and 5 produce adequate spreading of the stream and,inasmuch as it is easier to control the operation, their use is oftenpreferred.

The material discharged on rotor 28 or 38, as the case may be, ispartially bonded thereto to form a molten ring, but is mostly projectedtangentially from the rotor in a spread, distributed, or partiallydisintegrated stream which, at least for the most part, strikes rotorl6. Some of the material may also pass directly from rotor 28 or 38 torotor l8. The material discharged onto rotor I5 is partially bondedthereto to form a ring of incandescent material, the grooved surfacepromoting such bonding, and the excess material over that bonded isdischarged by rotor l6 onto rotor 18 where it, together with anymaterial reaching rotor [8 directly from rotor 28 or 5. fly' bonds toathe :surface of the :rotor ito :form an incandescentring of the moltenmaterialflbonm ins lot the :material again being :promoted. :bythe-grooved :surface. Any excess of the molten materlelover fthatbondedmay-again be projected backegains't motor [6, this=action-continuingnintil the excess material is bonded :to one -or theother-of the rotor-s.

The high speed rotation-of rotors -I6 -and lli causes portions of theincandescent rings '-to be throwrror drawn from 'the rotors-by the'centrif ugalforcescreated, these portions being drawn out into long,fine fibers. Although rotors I 6 and" I8 perform the main fiberizingfunction, rotor-28 or-38, -dependi-ng upon which is u-sed,also-opcrates-as a fiberizer to a substantial extent. Rotor ZS or 35 mayalso flberizetoa minor extent, but itsprimary function is thatof-receiving'the stream of molten material, increasing its velocity, andinitiating its distribution on the other-motors.

(Zrltical features -of-the-=invention, as previouslypointed out, are theincrease in "velocity and the spreading or gradual disintegration 0f thestream as it passes to the main flberizing rotors, whereby'the materialbonds thereto rather than being-thrown off or splattered and lost aswouldbe the case if-a concentrated, high volume stream :of .the typehere used was discharged directly and :perpendicularlyvonto the highspeed rotor iDI rotors.

The particular dimensionsof the rotors are not criticaluvithinreasonable limitsand may be selooted; on'th'e basis ofthecapacity desired; i. e., the uantity per hour of molten material tobe delivered by the meltingfurnace. However, the sizeirelationshipbetween .these elementszis preferably approximately that illustrated inthe drawings. atiwhich the rotors are-driven Will depend upon the;operating conditions, Suchas the --.-fluidity:

of'theimolten material, and the like; but again, for-purposes .ofexample, it may :be stated that,

in employing; a: substantially conventional mine eralevvool; melt,successful operation was obtained byldriving rotors 28hr 36 and281or38atperiphe eral speedsin the ranges of 2500 to '5000 feet per minute and.6500 to..10,000- feet ;perminutc-,;whilerotors l6 and ltwere driveninranges of.-L2,000

to. .16,000-feet per minute and 1.4,000to 20,000 feet per minute,respectively; The peripheral speeds of the rotors, .the fluidity of themelt, andthe like, .may be varied .to meet, given conditions, as pointedout above. It will be understood, :however, that the moltenmaterialmustbezof a sufiiciently .high temperature, the specifictemperatime range depending upon the character ot the material, -.tomaintain the molten material on the surfaces. ,of the bonded rings .in ahighlyfluid or incandescent .state to. permit .fiberization .to take.

place,

The .fiber; formed as described. above may be collected v.in anysuitable manner .and .abinder be introduced if desired, either. beforeor after initial fiber collection, the particular appatatus. forthesepurposes forming .no part of theinstant invention.

The,.construction has been found to. deliver .a greatly-increased fiberyield over the earlier .types ofarotor .fiberization, apparatus. Theoriginal stream which. mayhaye a diameter of, say, is greatly. expanded.in Width when .reccivedon thesur'faoes of the main fiberiz'ingrotors.The

PrQduotion-of. fine fibers is enhanced 'throughtho Also, the particularperipheral speeds.

accelerationof thesstream and its.=.reduction-sirom an original,relatively solid stream to, .whattisin 1 effect, 4 azpartiallydisintegrated stream :or streams of droplets.

Having thusdescribed my :invention :inrathcr" full detail, itwill .beunderstood "that :these details need :not be strictly adhered to butthat various :changes .and modifications may suggest.

themselves to one skilled in the art, all .falling Within the scope ofthe invention aswdefined by the 'subjoined claims.

What I claim is:

"1. In an'apparatus for converting a molten raw material to fibershaving means for discharging -a fluid stream-of the molten material, theimprovement comprising means in the path of'the stream for spreading thestream laterally, said stream spreading means including a rotor'having aconed peripheral surface, a shaft supporting said fIOtOY'fOI' rotationwith said surface in thepath of the stream, a second rotor =having an'oppositely coned peripher-al surface, a shaft 'sup porting 'said secondrotor for -rotation with its: surface adiacentthe first rotor, saidshafts extending at'an acute angle to each other; a third path of thestream, a second rotor'havingav peripheral surface, and a shaftsupporting sald' second rotor for rotation with its surfaceadjacent'tothe surface of the first rotor'toreceive the material fromthe first rotor, a "third "rotor having an unobstructed, moltenmaterialretainingperipheral surface, meansmounting said third rotor forrotation with its peripheral surface in the path of. the materialdischarged cysaid stream spreading means, whereby a portion-of thematerialof said stream'is retained on said surface and anotherportion isthrown off,'a fourth rotor having an unobstructed, molten materialretain ing .peripheral surface, means mounting said fourth rotor .forrotation with its peripheral surfacein the path of the materialdischarged bysaid third. rotor, and means for rotating said rotors.

3.. In an apparatus for converting a molten raw materialtofibershavingmeans for discharging a fluid stream of .the .molten material, the improvementcomprising means for spreading thestream, .saidspreading meansincluding a frusto-conical rotor, a shaft supporting said rotor for.rotation. on an approximately horizontal axis, asecond frusto-conicalrotor :in reversed) relationshiptosaid first rotor, a shaft supportingsaid .second. rotor for rotation on an approximately. horizontal axisand 'means for r0,-

tatingsaid rotors inopposite directions; a third rotor'having. aperipheral surface with means to.

retain molten. materialthereon, a shaft mountingsaid. third rotorforrotation withits peripheral .surfacein. the path of material dischargedby the spreading means, whereby a portionofj the material is retained onthe rotor and another portion is thrown off, a fourth rotor having aperipheral surface with means to retain molten material thereon, a shaftfor mounting said fourth rotor for rotation with its peripheral surfacein the path of the material thrown off by said third rotor, and meansfor rotating said third and fourth rotors in opposite directions at highspeeds.

4. An apparatus as defined by claim 2, having means for yieldablysupporting the shafts for the rotors.

5. A method of making mineral wool from a molten mineral materialcomprising discharging a stream of the molten material onto theperipheral surface of a rotating rotor, discharging the material fromthe rotor onto the peripheral surface of an adjacent rotor rotating at ahigher peripheral speed to spread and divide the stream, discharging thespread and divided stream at a relatively high velocity onto theperipheral surface of a third rotor to form an incandescent ring thereonfrom a portion of the mater al, discharging another portion of thematerial from the third rotor onto the peripheral surface of a fourthrotor to form an incandescent ring thereon, and rotating said third andfourth rotors at higher speeds than said first and second rotors to formfibers from said incandescent rings.

6. In an apparatus for converting a molten raw material to fibers havingmeans for discharging a flu d. stream of the molten material, theimprovem nt co pri ing means for accelerating the stream including arotor located to have its peri heral surface in the path of the streamto receive the material and discharge it therefrom, m ans for rotatingsaid rotor, a second rotor having a eripheral surface to receivematerial d scharged by the first rotor, means for rotating said s condrotor at a hi her peripheral speed than the fir t rotor; and fiberi'zinmeans ineludin a third rotor having a molten material retainin p riheral sur ace, means mounting said rotor for rotation with itsperipheral surface in the ath of mat rial di char ed by the accel rat ngmeans, a fourth rotor havin an unob"tructed, molten material r tainineri heral surface, rneans mounting said fourth rotor for rotation withits p ph ral surface ad ac nt said third rotor, and means for rotatingsaid th rd and fo rth rotors at a speed greater than that of said fir-tand s cond rotors.

7. In an a a atu for converting a molt n raw mat rial to fiber havingmeans for di charging a fluid stream of the molten mate ial. theimprover ent compris ng means for spreading and accelerating the str amincludin a substantially cylindrical rotor having an annular surface,means suppo ting said rotor for rotation with its annular surface in thepath of the stream, a second, sub tantially cylindrical rotor having anannular surface and means supporting said second rotor for rotation withits annular surface adjacent the first rotor; and fiberizing meansineluding a third rotor having an unobstructed, molten materialretaining, annular surface, means mounting said third rotor for rotationwith its annular surface in the path of the spread stream, a fourthrotor having an unob structed, molten material retaining annularsurface, means mounting said rotor for rotation with its annular surfacein the path of material discharged by said third rotor, and means forrotating said rotors.

8. In an apparatus for converting a molten raw material to fibers havingmeans for dis-' charging a fluid stream of the molten material, theimprovement comprising means in the path of the stream for spreading andaccelerating the stream, said stream spreading and accelerating meansincluding a substantially cylindrical rotor having a peripheral surface,means supporting stream, a fourth rotor having an unobstructed, moltenmaterial retaining peripheral surface,

means mounting said fourth rotor for rotation with its peripheralsurface in the path of material discharged by said third rotor, andmeans for rotating said rotors at successively higher.

peripheral speeds.

9. In an apparatus for converting a molten raw material to fibers, saidapparatus having.

means for discharging the molten material, the improvement comprising, arotor in the path of discharged material to receive material and projectit therefrom, a second rotor in the path of material projected by saidfirst rotor to receive material from said first rotor and project ittherefrom, a third rotor having an unobstructed, molten materialretaining annular surface positioned to receive material projected bysaid second rotor, a fourth rotor having an unobstructed, moltenmaterial retaining annular surface positioned to receive material fromsaid third rotor,

and means for rotating said rotors.

10. The method comprising, discharging molten mineral wool formingmaterial and converting the same into fibers by intercepting dischargedmaterial on a rotating annular surface and project ing materialtherefrom, intercepting material projected by said surface on a secondrotating annular surface and projecting it therefrom, interceptingmaterial projected by said second annular surface on an unobstructed,molten material retaining annular surface rotating at high speed anddischarging material thereirom to anothe unobstructed, molten materialretaining annular surface rotating at high speed.

11. In an apparatus incuding means for discharging a stream of moltenmaterial, devices positioned in the ath of the discharged material forconverting the material into fibers, said 12. The method comprising,discharging molten mineral wool forming material and converting the sameinto fibers by intercepting discharged material on a rotating annularsurface and projecting material therefrom, intercepting materialprojected by said surface on a second rotating annular surface andprojecting it therefrom, intercepting material projected by said secondannular surface on an unobstructed, molten mate- EDWARD R. POWELL.

10 REFERENCES CITED The following references are of record in the fileof this patent:

Number UNITED STATES PATENTS Name Date Lessing July 18, 1911 White Nov.15, 1938 Buss Apr. 11 1939 Ramseyer May 27, 1941 Powell Oct. 14, 1947

1. IN AN APPARATUS FOR CONVERTING A MOLTEN RAW MATERIAL TO FIBERS HAVINGMEANS FOR DISCHARGING A FLUID STREAM OF THE MOLTEN MATERIAL, THEIMPROVEMENT COMPRISING MEANS IN THE PATH OF THE STREAM FOR SPREADING THESTREAM LATERALLY, SAID STREAM SPREADING MEANS INCLUDING A ROTOR HAVING ACONED PERIPHERAL SURFACE, A SHAFT SUPPORTING SAID ROTOR FOR ROTATIONWITH SAID SURFACE IN THE PATH OF THE STREAM, A SECOND ROTOR HAVING ANOPPOSITELY CONED PERIPHERAL SURFACE, A SHAFT SUPPORTING SAID SECONDROTOR FOR ROTATION WITH ITS SURFACE ADJACENT THE FIRST ROTOR, SAIDSHAFTS EXTENDING AT AN ACUTE ANGLE TO EACH OTHER; A THIRD ROTOR HAVING APERIPHERAL SURFACE, MEANS MOUNTING SAID ROTOR FOR ROTATION WITH ITSPERIPHERAL SURFACE IN THE PATH OF THE SPREAD STREAM, A FOURTH ROTORHAVING A PERIPHERAL SURFACE IN THE PATH OF THE MATERIAL DISCHARGED BYSAID THIRD ROTOR, AND MEANS FOR ROTATING SAID ROTORS.